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NEOS Interfaces to CONOPT

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The NEOS Server offers CONOPT for the solution of nonlinearly constrained optimization problems in AMPL format.

CONOPT is a feasible path method based on the GRG algorithm. CONOPT is well-suited to models with very nonlinear constraints. It is a fast method for finding a first feasible solution that is particularly well-suited to models with few degrees of freedom. Also, for models where many equations can be solved one by one, CONOPT will take advantage of this property. Similarly, CONOPT eliminates from the model intermediate variables only used to define objective function terms and moves the constraints into the objective function.

CONOPT is developed and maintained by ARKI Consulting and Development A/S in Bagsvaerdvej, Denmark. For more information, visit the CONOPT website.

Using the NEOS Server with CONOPT

The user must submit a model in AMPL format to solve a nonlinear programming problem. The examples section of the AMPL website provides examples of models in AMPL format.

The nonlinear programming problem must be specified by a model file with the options of a data file and a commands file. If the commands file is specified, it must contain the AMPL solve command. The commands file must not contain the AMPL model or data commands. The model and data files are renamed internally by NEOS.

The commands file may include AMPL commands and option settings for SNOPT. To specify solver options, add

option conopt_options "OPTIONS";
where OPTIONS is a list of one or more of the CONOPT options. See the document Using CONOPT with AMPL for a list of options.

Enter the location of the AMPL model (local file)
Model File:

Enter the location of the AMPL data file (local file)
Data File:

Enter the location of the AMPL commands file (local file)
Commands File:


Dry run: generate job XML instead of submitting it to NEOS
Short Priority: submit to higher priority queue with maximum CPU time of 5 minutes
e-mail address:

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Please do not click the 'Submit to NEOS' button more than once.

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